Not applicable.
1. Field of the Invention
This invention is in the area of foam seat bun forming molds, specifically a forming mold with a fastener strip recess having specially-shaped end walls which provide a snap-fit seal against the ends of the fastener strip.
2. Description of the Related Art
Foam seat bun forming molds having recesses which accommodate a hook or loop fastener strip to be molded into the seat bun are known in the art, U.S. Pat. No. 4,792,111 to Taguchi being one example. Several different approaches have been taken in the art to the problem of liquid intruding into the ends of the mold recess during the initial molding process and fouling the hook or loop fastening elements. Most of these approaches involve incorporating end seal means into the fastener strip itself, as exemplified by the following:
U.S. Pat. Nos. 5,500,268; 5,614,045; and 5,654,070; all to Billerant, disclose a sealing strip of loops, similar to the loop material which engages hooks in a hook-and-loop fastener, which is placed as a barrier across each end of the fastener strip. U.S. Pat. No. 5,900,303 to Billerant uses molded plastic blocks as end barriers. U.S. Pat. No. 4,784,890 to Black discloses film which is attached to the ends of the fastener strip and which extends beyond the ends of the strip; or as an alternate barrier, dam-like structures which are placed onto the ends of the fastener strip. Perimeter seals, in which the end seals are an integral part of the overall seal around the outside borders of the fastener strip, are shown in U.S. Pat. Nos. 5,766,723 to Oborny et al. and 5,786,061 to Banfield.
All of the above methods, however, have a major disadvantage in that the end seal means are an additional component which must be incorporated into each fastener strip, thereby adding cost and complexity to the fastener strip manufacturing process. In addition, such fastener strips cannot be manufactured and supplied to seat bun makers in a long continuous spool, from which the necessary length of fastener strip can simply be cut during the seat bun molding process. Instead, these fastener strips must be precut to specific lengths, finished with end seals, and then supplied to the seat bun maker. It can be appreciated that this latter approach is inflexible and disadvantageous to the overall seat bun manufacturing process.
Alternate approaches to end-sealing the fastener strip have also been taken, and these involve sealing dams or ridges which are built into the forming mold. U.S. Pat. Nos. 5,665,449; 5,795,640; and 5,840,398; all to Billerant, illustrate examples of this alternate approach. These devices avoid the problem of having to incorporate end seals into each fastener strip; however, a major disadvantage of these devices is that they rely on magnetic or other hold-down means to force the fastener strip down onto the dam or ridge, in order to seal effectively during the molding process. If the magnetic or other hold-down force is weak or not positioned properly, these types of end seals will not seal effectively, and fouling of the fastening elements can occur.
Japanese Patent No. 6-91662 discloses a recess side wall with an inward bevel. However, this recess wall is differently-shaped than in applicant""s device, and does not provide the advantages of applicant""s specially-shaped walls. Specifically, the upper portion of the wall does not curve outward away from the interior of the recess, and thus does not form an entry bevel as in applicant""s invention.
A beveled or curved fastener strip entry point provides a critical advantage, because it greatly facilitates snapping the fastener strip into place, by allowing the end of the fastener strip to xe2x80x9cride downxe2x80x9d the entry bevel and then snap back into the lower portion of the mold wall. In addition, it greatly facilitates removing the fastener strip from the mold without tearing the fastener strip away from the finished seat bun, or otherwise damaging the bond between the fastener strip and the seat bun. The device of the Japanese patent does not have these important features or the advantages they convey, and is thus unsatisfactory.
Accordingly, several objects and advantages of the invention are:
The invention provides a means of end-sealing a mold-in fastener strip which does not have to be incorporated into each and every fastener strip, and which does not depend, in order to seal effectively, on the magnetic or other means used to hold down the strip.
Due to the specially-shaped end walls, and particularly the entry bevel, a fastener strip can be quickly and easily snapped into the mold recess of the invention, and the finished seat bun (with the in-molded fastener strip) can be easily withdrawn from the mold after molding is complete.
The invention can be used with many different types of fastener strips, and because the end seal means are incorporated right into the mold, the fastener strips can be made at a lower cost and with less manufacturing complexity. This allows the use of fastener strips which can be manufactured and supplied to seat bun makers in long continuous spools, rather than in precut pieces of specific and relatively short length.
The invention can be employed in forming various other items having in-molded fastener strips, not just foam seat buns.
Further objects and advantages of the invention will become apparent from a consideration of the drawings and ensuing description.
The invention is a seat bun forming mold with a recess suitable for containing a fastener strip to be molded into the seat bun, the recess having end walls shaped so as to provide a snap-fit seal against the ends of the fastener strip, in order to prevent fouling of the fastener strip during the seat bun molding process.